Odontoblast-like Cytodifferentiation of Dental Stem Cells: A Review

Dental problems are common in human populations. Traditional treatments are focused on managing caries, soft tissue impairments, functional defects, poor aesthetics, digestive disorders and alveolar bone resorption. During the last two decades, basic and clinical researches on adult stem cells have established a potential therapeutic concept in tissue regeneration. Among major cells responsible for tooth development, odontoblasts play a key role in the formation of organic and inorganic constituents of dental tissue. A premier stride in the development of novel stem cell-based strategies for the treatment of reversible and irreversible pulpitis is odontoblast regeneration. Among different candidate cell sources for odontoblastic regeneration, use of dental adult stem cells is a preferred option because of their great ability to differentiate into odontoblasts and also their minimally invasive isolation procedure. This review emphasizes on articles that report successful odontoblast-like differentiation of dental mesenchymal stem cells which in turn provide a background for dentin-pulp complex cell therapies, using genetic or chemical manipulation. The series of experiments both in vitro and in vivo asserted that dental mesenchymal stem cells can efficiently differentiate into functional odontoblast-like cells. However, the review shows there are drawbacks in present methods. Future research should focus on optimizing protocols on odontoblast differentiation of dental stem cells by simultaneously introducing different genes with mutual synergy, combined with chemical or recombinant protein introduction.Keywords: Dental Mesenchymal Stem Cells; Differentiation; Odontoblas

The Most Common Comorbidities in Dandy-Walker Syndrome Patients: A Systematic Review of Case Reports.

OBJECTIVE: Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities. METHODS: Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports. RESULTS: Diagnosis was most often set in 12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability. CONCLUSION: The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years

Structural and Functional Reorganization of the Brain in Migraine Without Aura

It remains unknown whether migraine headache has a progressive component in its pathophysiology. Quantitative MRI may provide valuable insight into abnormal changes in the migraine interictum and assist in identifying disrupted brain networks. We carried out a data-driven study of structural integrity and functional connectivity of the resting brain in migraine without aura. MRI scanning was performed in 36 patients suffering from episodic migraine without aura and 33 age-matched healthy subjects. Voxel-wise analysis of regional brain volume was performed by registration of the T1-weighted MRI scans into a common study brain template using the tensor-based morphometry (TBM) method. Changes in functional synchronicity of the brain networks were assessed using probabilistic independent component analysis (ICA). TBM revealed that migraine is associated with reduced volume of the medial prefrontal cortex (mPFC). Among 375 functional brain networks, resting-state connectivity was decreased between two components spanning the visual cortex, posterior insula, and parietal somatosensory cortex. Our study reveals structural and functional alterations of the brain in the migraine interictum that may stem from underlying disease risk factors and the “silent” aura phenomenon. Longitudinal studies will be needed to investigate whether interictal brain changes are progressive and associated with clinical disease trajectories

The effects of mineral trioxide aggregate on osteo/odontogenic potential of mesenchymal stem cells: a comprehensive and systematic literature review

The significance of dental materials in dentin-pulp complex tissue engineering is undeniable. The mechanical properties and bioactivity of mineral trioxide aggregate (MTA) make it a promising biomaterial for future stem cell-based endodontic therapies. There are numerous in vitro studies suggesting the low cytotoxicity of MTA towards various types of cells. Moreover, it has been shown that MTA can enhance mesenchymal stem cells' (MSCs) osteo/odontogenic ability. According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA), a literature review was conducted in the Medline, PubMed, and Scopus databases. Among the identified records, the cytotoxicity and osteo/odontoblastic potential of MTA or its extract on stem cells were investigated. Previous studies have discovered the differentiation-inducing potential of MTA on MSCs, providing a background for dentin-pulp complex cell therapies using the MTA, however, animal trials are needed before moving into clinical trials. In conclusion, MTA can be a promising candidate dental biomaterial for futuristic stem cell-based endodontic therapies

Comparing the effect of a simulated action potential simulation and vibration in reducing neck and shoulder pain and disability in patients with trigger points in trapezius and levator scapulae muscles

Background: Trigger points in the posterior neck muscles are the outcomes of most common types of musculoskeletal disorders. This study aimed to compare the effects of action potential (AP) simulation and vibration in reducing neck and shoulder pain and disability in subjects with trigger points in the trapezius and levator scapulae muscles. Materials and Methods: In this single-blinded randomized controlled trial, 30 patients with trigger points in upper trapezius and levator scapula muscles were randomly assigned into two equal groups. In the vibration group, moderate pressure-low frequency vibration was used for 25 minutes and in the AP group, the simulated AP with an intensity of 1mA was applied for 16 minutes. Before and after the treatment, neck disability was assessed using neck disability index neck pain using visual analogue scale shoulder pain and disability using pain and disability index and the ROM using a goniometer. A 16-session therapeutic plan was performed for both groups. Results: Visual analogue scale was decreased from 7±2.07 to 2±1.13 in the vibration group and from 7.13±1.95 to 2.12±1.06 in the APS group neck disability index was decreased from 26.66±2.56 to 15.33±1.88 in the vibration group and from 26.06±1.83 to 15.06±1.94 in the APS group (P<0.0001). There was no significant difference between the two groups regarding the total variables of the study. Conclusion: In participants of the study, both vibration and simulated AP not only can decrease the pain and disability in neck and shoulder, but also increase the ROM in the neck

Rapid and high-density covalent immobilization of Rhizomucor miehei lipase using a multi component reaction: application in biodiesel production

Aldehyde-functionalized silica and silica nanoparticles (SBA-15) were prepared as a matrix system for enzyme immobilization. Immobilization of Rhizomucor miehei lipase (RML) on these supports was performed via a multicomponent reaction under extremely mild conditions (25 °C, pH 7). Investigation on the mechanism of this reaction confirmed the Ugi four-component immobilization approach. The loading capacity of the supports and specific activity of the immobilized derivatives were interestingly improved. The results revealed very rapid immobilization of 10 and 60 mg of RML on 1 g of aldehyde-functionalized silica and SBA-15 after 10 and 30 minutes, respectively. Leaching experiments were performed by incubation of the immobilized derivatives in 1 M NaCl solution. The lack of the free lipase in the solution confirmed the covalent nature of the linkage. The thermal stability and co-solvent stability of the derivatives in the presence of three polar organic solvents (1-propanol, 2-propanol and dioxane) were greatly improved compared to the soluble enzyme. Both the derivatives were also used to catalyze the transesterification of colza oil with methanol to produce fatty acid methyl esters (FAMEs). In the case of RML immobilized on SBA-15 (SBA-RML), the presence of 40% of tert-butanol (v/v) as solvent in the reaction medium largely improved the conversion yield.Mehdi Mohammadi, Maryam Ashjari, Shaghayegh Dezvarei, Maryam Yousefi, Mohadese Babakic and Javad Mohammadi